Airship



Julyzz,1969 H. E. R. PAPST l 3,456,903

` AIRsHIP Filed April 7, 1967 4 Sheets-Sheet 1 ZmMg//MM July 22,1969

Filed April v, 1967 4 Sheets-Sheet 5 H. E. R. PAPST AIRSHIP July 22,1969 4 Sheets-Sheet 4 Filed April 7, 1967 FIG.1

FIGM

United States Patent O 3,456,903 AIRSHIP Hermann Ernst Robert Papst,Kark-Meier Strasse 1, St. Georgen, Black Forest, Germany Filed Apr. 7,1967, Ser. No. 629,167 Claims priority, application Germany, Apr. 9,1966, I 39,186; Dec. 24, 1966, P 41,101 Int. Cl. B64b 1/58, 1/06, 1/36U.S. Cl. 244-30 21 Claims ABSTRACT OF THE DISCLOSURE An airship providedwith a non-rigid double wall insulating envelope and utilizing watervapor and gas Ias a lift medium. The insulating agent used within theenvelope is air which is blown between separated double walls of theenvelope. The airship is also provided with bow and stern jets forpropelling and steering the airship.

Brief description of the invention The invention concerns an airshipand, more specically, an airship which operates with water vapor and gasas a lift medium in a ships hull and through a novel type of insulatingenvelope operating mainly with air as an insulating agent, as well asthrough a special development which can be utilized in such anadvantageous manner that the transportation costs of such an airship forboth freight and passengers will be considerably below the costs oftraditional means of transportation, such as railroad, air and highwaytransportation. The invention makes such airships a generally practicalmeans of transportation.

The airships that have been built in the past were filled, as a rule,with hydrogen or helium as a lift gas. The noncombustible helium,however, is very expensive and, therefore, makes the operation ofairships as a mass means of transportation uneconomical; hydrogen, onthe other hand, is so dangerous that its use in airships for passengertraic is no longer permitted because of past catastrophies.

As early as 1908, the proposal had been made to use superheated steam asa lift agent of airships. The use of superheated steam, however, hadbeen proposed for rigid dirigible airships, since the assumption wasmade that only in rigid dirigibles could the insulating agent,consisting of down, be placed around the individual cellules. (GermanPatent 214,019.) Also the lift of water vapor was too small to carry theexpensive multipartite frame construction of a rigid dirigible,consequently a plurality of gas bags were required to provide theadditional necessary lift for the frame and insulating agent.

It is the purpose of this invention to create an airship which willsatisfy the present day requirements made of transportation means withregard to safety, especially against the danger of re and explosion, aswell as with regard to economy in production and operation. It is lalsoan object of this invention to provide an airship suitable under presentday conditions for the transportation of passengers and goods evenyacross long distances and which is largely independent of landingplaces.

The invention comprises specifically a nonrigid airship constructed in anew manner, utilizing a new type of system for the lift, and also, aboveall, the construction of a new type of insulating envelope, a new typeof propulsion system, a new type of construction of the keel frame or ofthe rigid operating and transportation spaces carried by the airship, aswell as devices and the production process for the connection of severallayers of the insulating envelope. It is also within the scope of theinvention to provide the outside skin of the envelope with anonabsorbent layer, in order to reduce air resistance and loading downthrough precipitation. Within the framework of the invention of a newusable airship operating with water vapor, there will also be means toenable the safe handling of the airship in all kinds of weather by quickand firm anchoring at landing places, especially on roofs of buildings.

The nonrigid airship has a big advantage as compared to the rigiddirigible in not needing an expensive, complicated construction for thesupport of the envelope. Instead of a plurality of gas bags, it willessentially get along with one large cellule for the water vapor,whereby the balancing air cells, preferably housed in the bow and thestern, are heated and carried along with it. A nonrigid airship also hasthe advantage that expensive docks are not required for docking theairship and that after blowing off the lift medium, the nonrigidenvelope is rolled up or folded. The use of water vapor according to theinvention is advantageous, not only because of the greatly changeableshares of cold or heated air in the balancing and trim cells in suchnonrigid airships, but also especially, because during blowing of of thelift medium no considerable economic losses will occur, as is the casewith such lifting mediums as helium or even hydrogen, which arediliicult to replace.

Only the combination according to the invention, in using water vaporand air as a lift medium in a nonrigid airship with an insulatingenvelope, makes possible the creation of an airship, which iseconomical, safe and reliable for the transportation of mass freight andpassengers -across any desired distances. The high condensation heat ofthe water vapor of 330 kcal./m.3 gives a good thermal stability asagainst a pure gas illing. A further advantage of the vapor and airfilled airship, according to the invention, consists in this, that thelift can be greatly altered, at little cost, to the specificrequirements given through load and atmospheric conditions, by blowingin or condensing fairly large quantities of steam with a resultingchange in the temperature of the special air lled trim cells. The changein temperature can also be aided by the subdivision of the envelope byheated insulating sheeting.

If, for example, a load is discharged, then first of all one wouldattempt to leave the gas and heat content of the airship unchanged and,instead of the load, take in a corresponding amount of ballast,preferably water. This will cost the least; the only cost will be forthe operation of the pump.

If this is not possible, then one will iirst of all displace the warmair contained in `the bow and stern balancing cells with fresh airintroduced into the cells through the blowers producing the gas cellpressure. If the airship only has about half the maximum load on board,then one will be able to compensate largely for the discharge of theload without any balancing through ballast by an exchange of warm forcold air.

For larger loads, it will iirst of all be necessary to produce moresteam. The latter is then condensated up to about half the weight of therest of the load that is remaining to be discharged after the exchangeof air. The water that has been formed will balance out the lift of theremaining quantity of steam. Therefore, for the recreation of thebearing power for a new load, one -needs to evaporate this condensateagain and one needs only to heat up the air in the trim cells.

For very large loads, one ills the envelope of the non` rigid airshipwith steam, except for a very small fraction of air in the trim cells.If one blows off this steam, into the atmosphere for some reason orother, up to the point of the necessary lift for the airship itself,then one will have to either load anew or produce on board a likequantity of water from steam instead of the weight of the load. Thiscosts about DM 700.00 for 100 t. of load at DM 100.00 for 1 t. ofheating oil or natural gas. This is the most expensive but, at the sametime, also the quickest method for compensating for load.

The propulsion of the airship according to the invention takes placeadvantageously exactly in its axial direction by means of air currentsproduced in special blowers, which air currents are blown out throughslotted rocket jets positioned in the bow as well as in the stern. Theslotted rocket jet in the bow has been provided with guide means todeflect the expelled air current backwards, glidingly along the bowsurface during normal flight. With that, a part of the propulsive energyis introduced directly into the flight counter-current and thus the gasshock pressure of it on the envelope is decreased. This will permitgetting along with a lighter envelope for a certain required safetyfactor.

Beside the lift steam, one can advantageously also use a certainquantity of -a combustible gas producing a lift. This combustible gas,such as natural gas (methane) or hydrogen, is stored either in separatecells surrounded in a iireproof manner by noncombustible water vaporand/ or they are directly added to the water vapor. The gas which isadded directly is added at the most in such a quantity that there is nodanger of its igniting if the mixture somehow escapes into the air. Thecombustible lift producing gas that is consumed by the driving enginesor the steam producers for the heat reserve of a motor at standstill,approximately equals the amount of heat value supplied. This method ofoperation will avoid changes in lift and allows, at the same time, amaximum measure of heat being carried along by the airship in itstravel. Insofar as the natural gas which had been loaded is notconsumed, it increases the loading capacity of the airship through thelarger carrying capacity as compared to water vapor (plus 12% Removal ofthe light gas takes place directly from the special cells or else thegas can be separated from the water vapor by means of condensation ofsaid water vapor.

Furthermore, in accordance with the invention, the nonrigid envelope ofthe airship can be secured to the keel frame containing all of thespaces for operation, for machines and for transportation, whereby saidframe has been developed in such a manner, that when it settles down onthe ground a sealing path is formed in a resilient manner between theIground and its entire bottom surface or with the reinforced skeletonframe.

For securing the airship, according to the invention, on the ground,provision has been further made to provide the entire bottom side, orthose portions of it which have been formed as suction cups, withsuction fans, preferably with a driving blower, so that the airship willbe sucked in with great force to the ground after setting down.Furthermore, it has also been proposed to provide the bottom side of thekeel frame with pull magnet plates, which will produce, when the landingsurfaces are studded with steel plates, an additional anchoring forcethat would augment the suction hold. One can produce with edgewise fiatrods made of iron and with ceramic, placed in-between said rods,grid-like permanent magnets. With about 200 kg. expenditure of weight,50 t. of magnetic attraction per square meter is produced by such amagnet.

For example, an airship according to the invention, for thetransportation of 75 t. of freight or about 400 passengers on seats, ata diameter of 53 m., a length of 170 m. is required. It has an air layerinsulation of 0.3 m. thickness, which lets through 9 kcal. of heat perm.2h., at a 100 C. temperature difference. Its shape is about 'that of aspindle. Slotted rocket jets for propulsion and control are positionedat both ends. The attainable speed in the case f development as afreight airship will amount t o approximately 160 km./h. In the case ofa flying speed of 70 km./h., the loss of heat by the lift media, vaporand air, through the insulating envelope, will be compensated fo'i bythe exhaust heat of the engines.

According to the invention, if loads are to be discharged from theairship on nonprepared landing places, then first of all the lift isdecreased by an exchange of warm air for cold air in the bow and sterncells. The intermediate walls in these cells, which can be invertedinside the outside envelope in the manner of a nightcap toward thesteam-lift chamber, also have heat insulating double walls and areprovided with tension members. Therefore, air can be blown between theintermediate double walls or can be sucked out of the walls, so that thepassage of heat from the steam-lift chamber to the cells can be blockedor somewhat impeded when desired. The air temperature in the bow andstern trim cells can be changed independently of the vapor space on thebasis of this principle. An exchange of cold for warm air requires only1l kg. of heating oil or 16 cbm. of natural gas (100 C.) for theproduction of 1 t. of lift and this costs about DM 1.00 to DM 1.50.

If all warm air in the bow and stern cells is blown out and displaced byfresh air, one can either let out water vapor in the case of a biggerchange of the load or one can condense said water vapor more, and thelatter is most advantageously accomplished when one blows the fresh airthrough the bow and the stern cells for sometime and thus carries offthe required quantity of steam heat. For this purpose, the intermediatewall is -ventilated so that it will have an at least 100 times bettercapacity for conducting heat as compared to the insulating effect. Theballast water that is formed consumes approximately the lift of an equalquantity of steam. For new transportation tasks it will then benecessary to use approximately 35 g. of fuel oil or about 50 m.3 ofnatural gas at 100 C. for the production of steam per l t. of liftingforce. The lifting cost for a load that is to be taken up thereforeamounts to only about DM 3.50 per 1000 kg. If this airship hovers for 1hour without its engines running, then the lift will be maintainedthrough combustion of 25 kg. of fuel oil or 35 m.3 of natural gas at100?v C. In the case of this value, let us figure with an effective heatemission surface of about 20,000 qm. Every mi'nute of stopping timewould therefore cost about DM 0.05.

The outside surfaces of the envelope of the new airship are completelysmooth in order to have only a small surface resistance. Anyconstructional protrusions for steering or for the motors have beenavoided. The required useful spaces and the engine installation arehoused in' their entirety in the keel skeleton, whereby this has beencalculated statistically in such a manner that even with a full load, itcan still rest with merely two points atits two ends on the landingplace.

Advantageously, the keel skeleton consists of a strong latticeconstruction, preferably made of aluminum extrusion pipes, in which thepropellent is housed preferably in foldable containers protected in aiireproof manner and subdivided.

During the operation of the airship, the loss of heat 1s so small as aresult of the insulating envelope according to the invention, that asteam airship of the above-mentioned measurements can hover for 200 dayswith a payload. At km./h., a liying distance of more than 100,000 km.Acan be achieved if in the blister in the water vapor 75,000 m3 ofnatural gas (100 C.), as well as 53 t. of oil have been taken along,which would cost about DM 11,000.00. The simultaneous use of gas and oildoes not influence the lift conditions of the airship. The liftingforce, through steam and warm air, available for the payload and theconstructional elements of the airship, at the same time amounts toabout ll2 t. The envelope in a design for four-fold safety at a maximumdynamic pres: sure of 1,50 mm., uses up 32 t which is suicient forabout200 km. speed. The keel skeleton, the engines, improvements as well aspropulsion according to an estimated calculation require 45 t.Therefore, 30 t. of payload and 5 t. for reserve will be left over.

For shorter distances up to 2000 km., at 100 km./h. and 1000 H-P ofpower output, the payload for a freight ship will be around 50 t.higher.

Because of the omission of steering surfaces and the avoidance of ahitherto customary eccentric drive system which has been replaced by anaxial drive positioned simultaneously at the bow and the stern, the newsteam airship can be developed with a diameter to length ratio of about1:2 to 1:3, Which is much more favorable for propulsive resistance. Inthis way, the ratio of capacity to surface has been considerablyimproved. Rigid airships that were constructed had a ratio of D:L=l:5and more. The portion of the entire resistance from pure drag amountedto while the resistance of protruding constructional elements amountedto 28% and the surface resistance amounted to 57%.

Only through omission of the tail unit and of the outlying motornacelles as Well as through the stabilization of the drive by means ofthe driving and steering system through the jet propulsion drive, on bowand stern of the new airship, has the shorter shape become usable.

As a result of the reduction in surface area, the heat losses will becorrespondingly lowered. As a result of that, there is no longer anynecessity to subdivide the lift space occupied by steam and otherlifting gases. It has been found that it is simpler and more economicalto utilize the expenditure required for the subdivision of the cells foran increase in the strength of the envelope. The outside wall of theenvelope, in the case of the type of construction provided, can be lightand can be developed strong enough, so that a higher barometric pressureof the lifting gas, occurring in the case of a slanting position of theairship, can be absorbed with maximum safety.

Airships that were built hitherto also had the disadvantage that theycould execute control movements with their tail unit, only at a properspeed which also produced an aerodynamic lifting force. The axial driveaccording to the invention with a flow around the hull of the ship willpermit one to achieve control movements even at a standstill of the shipwhen one of the drives, either on the bow or on the stern, is reversedin its directional action.

The heat insulating outside envelope of the body of the ship accordingto the invention, consists of double walls which are connected with manycontinuous bands, said bands subdividing the space between the doublewall. The bands are in tension and are held at a distance by thepressure of a gas lled in-between the double wall, said gas beingpreferably air, which pressure surpasses by at least the barometricdegree of pressure, the pressure of the lifting gas acting upon Itheinside part of the wall serving as a cellule. Therefore, the doubleWalls of the body of the airship have the heat insulating distance atevery place. Convection movements of the gas are prevented by thetension bands. The distance of the cross bands is in the order ofmagnitude of centimeters, for example 5 cm., while the distance of thedouble walls from one another amounts to a multiple of that, for example30 cm. For the reduction of the radiation of heat, the cross bands arecovered preferably on their inside with a heat reecting metal layer.Preferably, an evaporated lm consisting of aluminum is applied, whichneeds only to be thin and which is economically usable for even severalhundred thousand square meters.

For maintenance of the distance of the Walls of the envelope from oneanother across the entire surface, the gas pressure between the walls ofthe envelope must be higher by at least the barometric degree ofpressure of the lift gas than the pressure of said lift gas. Accordingto the invention, this difference in pressure is produced advantageouslyby means of a continuously running auxiliary blower, which sucks up airfrom the trim cells and, as a result of that, assures the requireddifference in pressure without complicated controls. The end cells ofair are lled by other blowers, preferably by the blowers for theproduction of jet propulsion air. The pressure in the lift gas,therefore, is less per se than the ,required counterpressure for theoutside dynamic pressure, because the pressures in the gas chamber andin the intermediate Wall are superposed or inlluence each other. This isaccomplished by the effective connection between the outside double wallof the envelope by means of tension bands, said bands being evenlydistributed, because they have to be tightened in order to maintain thedistance. This can be utilized to make the gas cell pressure, exertedupon the lift gas in the case of a nonrigid airship, las low aspossible, in order not to decrease the lift values. Even with very thinfoils, used as surface-like tension bands, one will easily achieve a-fold safety for them and for the adhesive and welded connections.

For the purpose of protecting the envelope against sun and weather, theactual carrying layer is covered on all sides with a aluminum foil whichis impervious to moisture and light, and which in turn is protectedagainst corrosion and the occurrence of sudden leaks by being coveredwith -a polyvinylidene fluoride foil, which is resistant for a long timewith regard to sunlight and weather. Such a foil, which has been tested,is available on the market under the trade name Tedlan However, otherfoils too can be used which have this characteristic and which on top ofthat are nonabsorbent or, to express it in other words, water repellent.With such a nonabsorbent layer, atmospheric precipitation will not makethe envelope wet but will run olf or will be blown off by the ow of theair about the body. As a result of that, a weighing down of the airshipwill be prevented.

According to the invention, the inside of the envelope of the doublewall facing the water vapor is also covered with an aluminum foil andwith a polyvinylidene uoride layer. First of all, a chemical attack ofthe water vapor on the tissue of the inside wall and the foils sealingit will be prevented; furthermore, the condensate will run olimmediately in very small droplets, so that the inside of the envelopetoo, will not be weighed down by water. The achievable payloadtherefore, will not be reduced.

For complete insulation, the prevention of a heat loss due to radiationis still necessary. Zig-zag shaped strips may be used which arepositioned between the connecting bands and are made of a very thinsynthetic material foil having an evaporated aluminum layer. With theuse of such strips, the loss of heat, which already is very small, willstill be cut in half. However, the strips may be omitted in airshipshaving a very good engine performance and increased exhaust heat,because there will be suicient exhaust heat at ones disposal tocompensate for the heat loss due to the radiation.

Furthermore, in accordance with the invention, the proposal is made toselect as the nonabsorbent material on the aluminum foil, a substancethat permits the aluminum foil to be heated in a high vacuum beyond thecritical temperature of the water vapor and air, the substance in thatcase not yet decomposinig but melting tightly onto the foil without anyremnants of water vapor being enclosed'. Such a layer, because of lowsurface tension, has no inclination any longer to bind a skin of watervapor from the atmosphere, as do all other materials. It is suspectedthat the particles of the boundary layer adhering close to the wall areheld rmly on this absorbed water vapor skin, on which the knownphenomena of flow will result during the tlow around bodies.

If, therefore, one should be successful in eliminating the Water vaporskin, then one could expect that no adhesive boundary layer would existlany longer but instead gliding boundary layers would exist. As a resultof that, the loss of low would be largely reduced.

Another statement of Itiuid physics makes the fluid friction disappearwhenever the bodies are smooth up to 10-8 cn., i.e., electron-optically.Through the melting process in the high vacuum which has been provided,with the simultaneous elimination of an adhesive possibility for thewater vapor skin, one must also expect that the surface of such a fusedlayer is also smooth electron-optically.

It is proposed to use such aluminum foil or foils or other metal withlayers applied in a high vacuum for the achievement of gliding of thetiow boundary layer (for the purpose of reducing the surface resistance)in the case of gases and liuids on or in watercraft, land vehicles,aircraft, machines and tools. The individual walls, according to theinvention, consist preferably of high strength fibers, for example, ofpolyterephthalic acid ester, with crossediilaments lying one beside theother, which have been woven in accordance with known processes, orwhich cross each other lying in parallel one beside the other. In thecase of tbe latter arrangement, the connection of the filaments isbrought about through a coating on an intermediate layer. According tothe invention, the outsides of the fabrics or of the crossing filamentshaving the intermediate layer are connected to tight, shift-proof4surfaces by means of a solid foil, preferably made from the same highstrength synthetic material, through an adhesive agent or through fusingby means of a welding process, for example, by means of ultrasonics.

In the case of an arship, the strength of the fiber or the number offibers` in the main stress direction of the fabric is made, preferably,twice as strong as in the longitudinal direction of the fabric of theenvelope. In this manner, an exceedingly light, highly constant envelopehaving great strength and safety is provided for the nonrigid arship.

The tiber web or cross web, sealed in the manner described, isadditionally, and according to the invention, saturated at its edgethrough connection with an incoming liquid mass of mastic, penetratingthe web, which enters by sections even in the cross direction, In thismanner, fields that have been closed in an air-tight manner, developbetween the cover foils and the periphery of the `sealing tracks, whichprevents moisture from spreading lthey are gradually reduced instrength. The inner and outer cover of this web of the double walls,therefore, protect the envelope of the arship from such a seasoning,since a metal layer, as is well known, is impermeable to water vapor andthe bottom layer protecting the metal in addition, will allow, like allhighly molecular synthetic substances, the water vapor to dilfuse.

. The connection of the individual sectors of the envelope made fromlengths of fabric is accomplished through overlapping adhering, wherebythe lengths of fabric cover each other up and also cover the syntheticfoils protecting the fabric. The adhesive connections are carried outad- `vantageously with a two-component adhesive or a Contact occurs inthe layer of air between the double walls.

Nevertheless, the envelope must be stable against a temperaturecorresponding to the water vapor, because one has it within ones powerthrough letting out the separating layer of gas between the doublewalls, to make those two labut against each other and to bring about aquick condensation of the water vapor, for exampleZ in. order todischarge a load or in order to stop the a1rsh1p and to store it.

The temperature of the water vapor can be reduced through admixture of agas. According to known laws, the water vapor will then haveacondensation temperature which corresponds to its partial pressure inthe gas mixture. Preferably methane is mixed for this purpose with thewater vapor, because this gas will increase the lift. Hydrogen can alsobe used as an additive, since it is not combustible if there is only asmall portion of it in the water vapor.

In the arship according to the invention, one could use a superheatedwater vapor, since the foils and the materials of the fabric of theinside wall would be able to withstand that because of the little stressput upon them. However, when superheated water vapor is used, one willlose the advantage of having the condensation temperature of the watervapor, the saturated steam temperature, as the highest temperature atall place, instead the temperature would be higher so that the safety ofcertain spots of the envelope against overheating could only be achievedwith complicated measures. Unfortunately, there is no other agent butwater vapor which, at the same time, must be taken into consideration asa lifting gas and which has a higher evaporation temperature.

The use of saturated steam, that is to say, the reserve of steam beingheated only a little beyond the boiling point, which can be easilyachieved by adiabatic expansion, will achieve, therefore, the greatestdegree of operational safety which is imaginable for an arship usingwarm gas for lifting force.

Additional advantages and areas of application of the arship accordingto the invention will become clear from the subsequent description takenin combination with the accompanying drawings in which:

FIGURE 1 shows the arship according to the invention with possibleinstallation in the envelope;

FIGURE 2 shows the arship according to the invention in the shape of aspindle and with a ratio of diameter/ length of 1/3;

FIGURE 3 shows the arship according to the invention with an aspectratio of 1/5;

FIGURE 4 shows a front view of the arship according to thel invention;

FIGURE 5 is a section through the double walled insulating envelope ofthe arship according to the invention;

FIGURE 6 is a section through the most extreme bow part of the arshipaccording to the invention;

p FIGURE 7 shows a section through the outermost stern part of thearship according to the invention;

FIGURE 8 shows a section through the keel frame of the arship accordingto the invention with the envelope folded up;

FIGURE 9 shows a design of the arship according to the invention with aseparate cell for the combustible gas and with end walls that can beturned inside out;

FIGURES 10, l1 and 12 show a device for application of a layer ofsynthetic material on a metal layer.

Detailed description of the invention According to FIGURE 1, the arshipaccording to the invention, consists of a keel frame 1 and an envelope2. The stern or the bow jets have been designated by 3 and 4. Inside theenvelope of the arship, there is a supporting frame 5, to whichstretching ropes 6 can be attached, which are capable of guiding theforces from the upper sideV of the envelope to the keel frame. If needbe, the envelope 2 can be subdivided by transverse walls 30.

FIGURE 2 shows the arship according to the invention in the shape of aspindle with a ratio D:L=1:3, which results in favorable air-resistancevalues and in a favorable surface volume ratio.

FIG. 3 shows a shape of the arship, according to the invention, forachieving higher speeds with an aspect ratio of 1 to 5.

FIGURE 4 shows a front view of the airship according to the invention,whereby one can recognize that the envelope 2 with keel frame 1 isattached to longitudinal bands 31. The nonrigid envelope 2 itself, ascan be seen in the drawing, has been entirely closed within the area ofthe keel frame.

During operation of the airship, the distance between the walls of theenvelope is maintained by gas pressure. According to the invention, thegas pressure is produced by means of a continuously running auxiliaryblower (schematically represented by box 40 in FIGURE 9) which sucks upair from trim cells 28 and 29 through intake lines 42, 42', and exhaustsair into the space `between the walls of the envelope through outletline 44.

FIGURE 5, furthermore, shows a section through the double walledinsulating envelope of the airship, according to the invention. As canbe seen, the following sequence of layers from the inside to the outsideof the envelope 2 has been provided: after the steam located inside theairship, there follows a non-moistening, that iS to say a nonabsorbentlayer 7 of synthetic material, which 'preferably consists ofpolytetrafluoroethylene or polyvinylidene uoride. However, one can alsouse other synthetic substances with the same effect. This nonabsorbentlayer of synthetic material has been applied to a metal foil 8 which issteam resistance and which consists preferably of aluminum. The twolayers may be connected with one another by means of the speciallydescribed temperature application process under a vacuum or a protectivegas. A binder layer 9 follows the metal foil 8, which binder layerconsists of a commercial binder of synthetic substances and Vwhich isapplied as a lacquer. With the help of this binder layer, the metal foil8 will be connected with the fabric layer 10 of synthetic material.

The fabric made of synthetic material consists perferably of polyesterwhich is temperature resistant beyond 100 C., however the possibilityalso exists to use instead of fabric, an arrangement of the threads as alleece, in the form of adjoining parallel and crossing threads which canbe bonded with one aonther. In order to absorb different tensions in thelongitudinal and in the peripheral directions of the envelope, one canselect, perferably, the ratio of warp/weft thread in such a manner-forexample, 2:1-that the stress upon the individual threads of the fabricwill be equalized. Furthermore, in order to prevent a bracing of thefabric in a diagonal direction, it is contemplated that in accordancewith the invention, the bearing layer of fabric itself could be coveredon one or both sides with a thin foil of the same material and that thefoil could be broken into fields that are sealed in themselves, throughstrip shaped penetrating impregnation. With strip shaped penetratingimpregnation, the foil is bonded with the fabric at least at eachimpregnated strip. According to the invention, continuous bands 11follow the fabric layer 10a, b, c. The bands 11 likewise consist of afabric made of synthetic material or of foils, and, to be sure, are madepreferably of polyester. The bands 11, furthermore, are steamed with analuminum layer 12 against heat radiation. They are welded together orbonded each time with the inside layer of a foil consisting of asynthetic fabric and with the outside layer 13a, b, c of a foilconsisting of a synthetic fabric. In the U-shaped space of thetransverse bands 11, surface sectors of a thin folded synthetic materialfoil 14 may also be provided. This foil 14 has preferably been coveredby way of vapor deposit with aluminum or some noble metal. The foils 14prevent heat radiation between the two layers of fabric 10a, b, c and13a, b, c, and they prevent, at the same time, convection of the airlocated in between them.

The outside fabric layer 13 is followed in the same manner as the insidefabric layer 10 by a bonding layer 15, then there follows a water vaporresistant metal foil 16 and a nonabsorbent layer 17. According to theinvention, the outside nonabsorbent layer 17 prevents rain, snow and dewfrom adhering to the airship, whereby the moisture runs otf the layer sothat no additional loading of the airship will occur through surfacemoisture.

The layers described above and according to the invention, have thefollowing dimensions, which should be considered as approximate values:the inside nonabsorbent layer 7 has a thickness of 25p, the inside metalfoil 8 has a thickness of 11n, the bonding layer 9, which is present inthe form of lacquer, has a weight of 4 g./m.2, the inside fabric layerhas preferably a thickness of 0.15-1 mm., while 'the transverse bands 11have a thickness of 5-25/t, and the metal layer 12, which was steamedon, has an approximate hickness of 0.1;t. The outside foil and fabriclayer 13a, b, c is the `bearing layer of the entire envelope. Itsthickness amounts to about 0.3 to 2 mm. The bonding layer of lacquer 15has an approximate thickness of 4p, the outside metal foil 16 has athickness of 11p., while the outside nonabsorbent layer 17 is 25, thick.

The double-walled insulating envelope according to the invention, at atemperature difference of C. for a wall distance of 30 cm. and at adistance of the cross bands of 5 cm., has a loss of heat of less than 17kcal./m.2h; and in the case of a wall distance of 30 cm. with foldingfoils 14, the loss of heat amounts to even less than 10 kcal./m.2h.

FIGURE 6 shows, furthermore, a section through the outermost bow part ofthe airship according to the invention. The compressed air, producedpreferably by diesel engines and propellers or blowers (the engines andpropellers `or blowers being schematically represented by boxes 46)driven by said engines and located in the keel frame, is supplied to thebow jet via an air supply pipe 18, which is also formed of fabric-typematerials. The air is distributed in slotted rocket jets with a mediumjet body 20 and exits from the inside of the deecting screen 19alongside the body of the bow. In the inner space of the jet body 20,there may be advantageously an observer or helmsman. The deflectingscreen 19 may be adjusted hydraulically by conventional controlsschematically represented by box 48 and hydraulic cylinders 50 whichinterconnect screen 19 with envelope 2 whereby the distance from theedge of the bow and may be adjusted laterally, and thus the airship maybe steered. Advantageously, the screen should be foldable, so that thebow jet will blow out a jet counter to the normal direction of travel.In this manner, it will be possible not only to propel the airshipaccording to the invention by means of the bow jet, as in the case ofthe normal position of the deflecting screen, but also to brake theairship with a folded up deecting screen. Lateral deflection of thecompressed air takes place by means of a shift of the jet body 20 fromits center position to one side of the edge of the slotted rocket jet.The overwhelming escape of air from one side to the bow nozzle producesforces, deviating from the line of the axis, which can be utilized forsteering.

Through the central backward flowing off of the compressed driving air,the dynamic pressure on the bow part of the airship is, at the sametime, reduced considerably, so that the necessary gas cell pressurebecomes lower.

FIGURE 7 shows a section through the outermost stern part of the airshipaccording to the invention. The air supply to the stern is accomplishedagain through an air supply tube 21, just as in the case of the bow.Corresponding in manner to the bow jet, the compressed air itself isproduced in the keel frame. The slotted rocket jet is again formedthrough a central jet body 22, which again is adjustable axially andradially to all sides from its middle position by hydraulic cylinders 52interconnecting the jet body 22 with envelope 2. By means of jetdeecting surfaces that can be put forth from the jet body 22, it ispossible to further deflect the stern jet. The jet body 22 can also bedeveloped just like the bow body 19 as an observation post.

FIGURE 8 shows a section through the keel frame 1 of the airshipaccording to the invention with a folded up envelope 2. The keel frame41 is fashioned of four longitudinally-running extruded sections oflig-ht metal pipes 23, which have large diameters. Therefore, it will bepossible to store propellants and other operating agents in the lightmetal pipes 23, which are subdivided into cells, in a fireproof mannerand shielded from the inside space of the keel frame. The four pipes 23are connected with one another either through longitudinal andtransverse walls or through diagonal trussings. This keel frame can bedimensioned to have a small weight evenly distributed for support at anytwo places, just as in the case of oceangoing ships. It can then land onany desired bearing sur face. The upper side of the keel frame can beprovided with sturdy cantilever walls 25, which, after blowing olf thelifting agent, permit the envelope to be folded together. With thisprocess, a separate airship shed becomes superfluous.

FIGURE 8, furthermore, shows the development of the keel frame 22 withsuction plates 32, which are attached either separately by themselvesbelow the keel frame, or else the entire bottom surface of the keelframe 1 is developed as a suction plate. On the sides of the suctionplates or the sides of the keel frame 1, tire elements 24, preferably ofa very strongly sealed fabric of synthetic material, have been attached.If the blower on the keel frame sucks away air, then a partial vacuumwill be created below the plate of the keel frame. This partial vacuumwill then hold the keel frame with the airship with great force on theground. Because the tire 24 is sealed at the edge of the keel frame 1 orthe suction plate 32, the sucking in can also take place on lawns, sandplanes and similar places. For sucking in air, one can also use theregular driving blowers. Additional equipment to produce a partialvacuum will then be unnecessary.

FIGURE 9 shows another design of the airship according to the inventionin which combustible gas is provided in a special cel1`33 located withinand surrounded by noncombustible gas. The cell 33 for the combustiblegas 15 is arranged in the middle of the airship. The cell walls 26consist likewise of a synthetic fabric sealed with a metal foil againstwater vapor. The water vapor surrounding the cell 33 protects thecombustible gas against the possibility of ignition.

The walls 27 and 28 can be turned inside out, and separate the steamspace from the air spaces. When air is blown between the double walls ofwall 27 or 28, the wall insulates the steam space from the respectivebow or stern cell. However, when no air is blown between the doublewalls, the walls 27 and 28 no longer insulate the steam space from thebow andstern cells. Thus, the air in the bow and in the stern cells 28,29 can be heated quickly or can also be blown through, by means of freshair, independently of the steam space. Usually, the air in the bow andstern part is hot and therefore contributes considerably to the lift ofthe airship. If the lifting force of the airship is to be decreased,then the warm air is replaced by cold air through the blower. Inversely,an increased lift may be obtained through the fact that the air in thebow and stern parts is heated, because of the freely running blower 19,a superpressure will be prevented.

FIGURE 9, moreover, shows in a dotted line the separating walls 27turned inside out. In this state, the airship contains the most air andthe least steam. The lifting force is the smallest.

Another possibility of storing the combustible gas without any dangerconsists in admixing the gas with the steam. At the same time, theadmixing ratio should be selected in such a manner that an ignition ofthe gas within the steam is impossible. To obtain the gas forconsumption, a part of the steam-gas mixture is drawn off and cooled, sothat the steam condenses and the gas is left over. The water obtained inthis manner again is evaporated by the exhaust heat of the drivingengines and is returned to the steam space. Suitably, the consumption ofthe gas and the consumption of liquid or solid propellants or similarthings is accomplished in such a manner that the reduced lifting force,on the basis of gas consumption is balanced by a steady decrease in thenecessary lifting force.

FIGURE l0 shows an arrangement for applying, on a metal foil, a layer ofa synthetic substance that does not adsorb layers of water vapor. A rollof aluminum foil in a vacuum is drawn through the annealing furnace,represented by two plates at about 400 C., said aluminum foil beingwound up by the right-hand winding roller. The fluorine resin plate hasbeen lifted off.

FIGURE 11 shows a further step of the process according to theinvention. The left winding roll is turned back, while the bloc-k ofresin is pressed against the heated roll (above on the right-hand side).The resin will melt between the heating plates onto the foil in thevacuum. The foil is then wound back again.

FIGURE 12 shows a further step whereby a neutral gas, free of watervapor and of high pressure, for example, argon of 16 atm., is allowed toenter the boiler. The iluorine resin layer ,applied is molten at ahigher tempera ture at the above-mentioned gas pressure withoutdecomposition.

In view of the properties of the synthetic material, the airshipaccording to the invention will advantageously be operated only withsaturated steam. In this case, the advantage of saturated steam lies inthe stability of the wall temperature of the envelope, because thecondensation temperature in the nonrigid envelope is equally higheverywhere. The disadvantage in the condensation of the saturated steamon the inside surface of the nonrigid envelope will be eliminatedthrough the non-absorbent layer.

The water condensing along the wall runs off and is then pumped away(pump 54, intake lines 56 and discharge lines 58 schematicallyrepresented in FIGURE 8), heated by means of the exhaust gas heat of thedriving motors 46 with exhaust gases passing through heating elementsschematically represented heating element 60, and is returned again tothe steam space. Superheated steam it is true, can also be used, but itrequires special regulating installations.

As described the airship is driven by ordinary engines, such as dieselengines. Still the fact should not be excluded that other driving means,such as gas turbines, atomic reactors, etc., can be used. Furthermore,if these driving agents do not liberate sufficient exhaust heat,additional direct heating of the steam could be accomplished. Such adirect heating of the steam is also necessary to keep the airshiphovering in the atmosphere without operation of the driving engines andalso for the purpose of filling it prior to its start. Since theadditional aggregates or the additional possibilities of use are clearto the expert, and no additional inventive process is required for theiruse, any further description of these is unnecessary here.

The coating of the outermost metal skin with a moistening, thereforenonabsorbent layer of synthetic material, has an additional advantage inthe fact that through this, the boundary layer can, under certaincircumstances, be considerably influenced and the friction resistance ofthe airship, which absorbs a considerable portion of the driving force,can be greatly reduced. Because of this surface, the air, so to speak,will glide past the airship without the formation of a boundary layer.

As can be seen in the foregoing description, which is not intended aslimiting in any way, but which is merely to give a single design by wayof example of a series of advantageous designs following the principleof the invention, the airship according to the invention is uniquelysuitable for the safe mass transportation of passengers and freight.

The safety factor is to be found especially in the fact that even in thecase of a very unlikely occurrence of large leaks in square meter areas,escape of the large volume of steam takes place so slowly that a safelanding of the airship Vwould still be possible.

While the preferred form of the invention has been shown and described,it is to be understood that all suitable modifications and equivalentsmay be resorted to which fall within the scope of the invention.

What I claim is:

1. Motor driven, maneuverable, non-rigid dirigible with a double wallenvelope around the volume of lifting gas, said double Wall being air orgas filled to separate inner and outer walls of said double wall,intermediate elements and surface sectors extending between said innerand outer walls for decreasing heat convection and radiation betweensaid inner and outer walls, character' ized in that:

said lifting gas comprising an essential portion of steam,

which, close to said envelope has saturated steam conditions;

said intermediate elements are tensile connectors se cured to andinterconnecting said inner and said outer walls radially, saidintermediate elements being collapsible and spaced a short distance inrelation to one another; and

said surface sectors are formed of thin strips of collapsible foil whichreiiect the heat and which are spaced close to one another for a zigzagconfiguration between said inner and outer walls and are secured to saidinner and outer walls.

2. The non-rigid dirigible according to claim 1 wherein -inside saidenvelope air filled stabilization cells are provided, said stabilizationcells having air or gas filled double walls with tensile connectors andzigzag-shaped heat reflecting strips of foil which extend between andare secured to said walls of said stabilization cells.

3. The non-rigid dirigible according to claim 1 characterized in thatsaid heat reflecting strips of foil are covered with a thin metal layer.

4. The non-rigid dirigible according to claim 3 characterized in thatthe said thin metal layer covering each of said strips of foil comprisesaluminum.

5. The non-rigid dirigible according to claim 3 characterized in thatthe said thin metal layer covering each of strips of foil comprises anoble metal.

6. The non-rigid dirigible according to claim 1 characterized in thatthe spacing between said inner and outer walls-of said double wallenvelope is greater than the spacing between adjacent tensileconnectors.

7. The non-rigid dirigible according to claim 1 characteribed in thatsaid inner and outer walls of said double wall envelope each have thinmetallic reflecting layers to retard heat radiation.

8. The non-rigid dirigible according to claim 7 characterized in thatsaid thin metallic reflecting layers of said inner and outer walls ofsaid double wall envelope are coated with a non-absorbent cover layer toprevent accumulation of water on said envelope.

9. The non-rigid dirigible according to claim 8 characterized in thatsaid non-absorbent layers comprise polytetraliuoroethylene.

10. The non-rigid dirigible according to claim 1 characterized in thatsaid inner and outer walls of said double wall envelope each comprise alayer of fabric made of synthetic fibers, veach of said layers beingcovered at least on one side with a thin foil.

11. The non-rigid dirigible according to claim 10 characterized in thatsaid layer of fabric has differing tensile strengths in the longitudinaland peripheral directions of the envelope with the strength in onedirection being twice as great as the strength in the other direction.

12. The non-rigid dirigible according to claim 11 characterized in thatthe ratio of warp threads to weft threads is at least 2:1 for thepurpose of absorbing different tensions in the longitudinal andperipheral directions of said envelope.

13. The non-rigid dirigible according to claim 1 characterized in thatthe air or gas between the inner and outer walls of said double wallenvelope has a pressure at least as great as the pressure of the liftingmedium within said envelope.

14. The non-rigid dirigible according to claim 13 characterized in thatthe gas or air in the interval between said inner and outer walls ofsaid double wall envelope is pressurized by means of a blower means.

15. The non-rigid dirigible according to claim 1 characterized in thatsaid lifting gas contains a portion of a combustible operating gas inaddition to said steam with the concentration of said combustibleoperating gas being below the concentration required for ignition.

16. The non-rigid dirigible according to claim 15 characterized in thatmeans is provided for separating said combustible operating gas fromsaid lifting gas for consumption of said combustible operating gas inthe operation of said dirigible.

17. The non-rigid dirigible according to claim 1 wherebow and stern jetmeans are carried by said double wall envelope along the longitudinalaxis of said envelope;

a rigid keel frame is carried on the underside of said envelope, saidkeel frame housing blower means, said blower means interconnected tosaid bow and stern jet means by supply pipe means;

said bow jet means comprising a first body adjustably secured to saidenvelope and having a surface configuration complementary to the surfaceof said envelope adjacent said first body and forming with said envelopea first annular opening for discharging compressed air to propel andsteer said dirigible, means for adjusting said first body both radiallyand axially with respect to the longitudinal axis of said envelope toregulate the size and configuration of said first annular opening foreffecting the propulsion and steering of said dirigible; and

said stern jet means comprising a second body adjustably secured to saidenvelope and having a surface configuration complementary to the surfaceof said envelope adjacent said second body and forming with saidenvelope'a second annular opening for discharging compressed air topropel and steer said dirigible, means for adjusting said second bodyboth radially and axially with respect to the longitudinal axis of saidenvelope to regulate the size and configuration of said second annularopening for effecting the propulsion and steering of said dirigible.

18. The non-rigid dirigible according to claim 17 characterized in thatsaid second body is conical in configuration and is mounted within andprotrudes from a cavity formed in said envelope.

19. The non-rigid dirigible according to claim 17 characterized in thatsaid first body has a detiecting screen in the form of a hollow,truncated cone which tapers toward the lbow of said envelope, saiddefiecting screen co-operating with said envelope to form an annular gapfor expelling compressed air in a generally rearward direction.

20. The non-rigid dirigible according to claim 17 characterized in thatthe rigid keel frame has a large essentially flat floor means whichextends substantially the length of the envelope, the underside of saidfloor means having an elastic seal which encircles at least a part ofthe underside of said fioor means and suction means carried in said keelframe and interconnected to the underside of said floor means to createa partial vacuum between a landing surface and the underside of saidiioor means.

21. The non-rigid dirigible according to claim 20 characterized in thatthe blower means within said keel frame for supplying compressed air tosaid bow and stern jet means also serves as said suction means.

References Cited UNITED FOREIGN PATENTS 5 MILTON BUCHLER, PrimaryExaminer STATES PATENTS IGmbel 244 125 RICHARD A. DORNON, AssistantEXaIIlIlel' Donnell et al. 244-30 Trey 24 30 Us. c1. XR.

Desmarteau 244-30 10 244-52, 61, 99, 126, 12S

